<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2006 - 2011 EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 2.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * CodeIgniter Caching Class
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Core
 * @author		ExpressionEngine Dev Team
 * @link
 */
class Cache extends CI_Driver_Library {

	protected $valid_drivers 	= array(
				'cache_apc', 'cache_file', 'cache_memcached', 'cache_dummy'
				);

				protected $_cache_path		= NULL;		// Path of cache files (if file-based cache)
				protected $_adapter			= 'dummy';
				protected $_backup_driver;

				// ------------------------------------------------------------------------

				/**
				 * Constructor
				 *
				 * @param array
				 */
				public function __construct($config = array())
				{
					if ( ! empty($config))
					{
						$this->_initialize($config);
					}
				}

				// ------------------------------------------------------------------------

				/**
				 * Get
				 *
				 * Look for a value in the cache.  If it exists, return the data
				 * if not, return FALSE
				 *
				 * @param 	string
				 * @return 	mixed		value that is stored/FALSE on failure
				 */
				public function get($id)
				{
					return $this->{$this->_adapter}->get($id);
				}

				// ------------------------------------------------------------------------

				/**
				 * Cache Save
				 *
				 * @param 	string		Unique Key
				 * @param 	mixed		Data to store
				 * @param 	int			Length of time (in seconds) to cache the data
				 *
				 * @return 	boolean		true on success/false on failure
				 */
				public function save($id, $data, $ttl = 60)
				{
					return $this->{$this->_adapter}->save($id, $data, $ttl);
				}

				// ------------------------------------------------------------------------

				/**
				 * Delete from Cache
				 *
				 * @param 	mixed		unique identifier of the item in the cache
				 * @return 	boolean		true on success/false on failure
				 */
				public function delete($id)
				{
					return $this->{$this->_adapter}->delete($id);
				}

				// ------------------------------------------------------------------------

				/**
				 * Clean the cache
				 *
				 * @return 	boolean		false on failure/true on success
				 */
				public function clean()
				{
					return $this->{$this->_adapter}->clean();
				}

				// ------------------------------------------------------------------------

				/**
				 * Cache Info
				 *
				 * @param 	string		user/filehits
				 * @return 	mixed		array on success, false on failure
				 */
				public function cache_info($type = 'user')
				{
					return $this->{$this->_adapter}->cache_info($type);
				}

				// ------------------------------------------------------------------------

				/**
				 * Get Cache Metadata
				 *
				 * @param 	mixed		key to get cache metadata on
				 * @return 	mixed		return value from child method
				 */
				public function get_metadata($id)
				{
					return $this->{$this->_adapter}->get_metadata($id);
				}

				// ------------------------------------------------------------------------

				/**
				 * Initialize
				 *
				 * Initialize class properties based on the configuration array.
				 *
				 * @param	array
				 * @return 	void
				 */
				private function _initialize($config)
				{
					$default_config = array(
				'adapter',
				'memcached'
				);

				foreach ($default_config as $key)
				{
					if (isset($config[$key]))
					{
						$param = '_'.$key;

						$this->{$param} = $config[$key];
					}
				}

				if (isset($config['backup']))
				{
					if (in_array('cache_'.$config['backup'], $this->valid_drivers))
					{
						$this->_backup_driver = $config['backup'];
					}
				}
				}

				// ------------------------------------------------------------------------

				/**
				 * Is the requested driver supported in this environment?
				 *
				 * @param 	string	The driver to test.
				 * @return 	array
				 */
				public function is_supported($driver)
				{
					static $support = array();

					if ( ! isset($support[$driver]))
					{
						$support[$driver] = $this->{$driver}->is_supported();
					}

					return $support[$driver];
				}

				// ------------------------------------------------------------------------

				/**
				 * __get()
				 *
				 * @param 	child
				 * @return 	object
				 */
				public function __get($child)
				{
					$obj = parent::__get($child);

					if ( ! $this->is_supported($child))
					{
						$this->_adapter = $this->_backup_driver;
					}

					return $obj;
				}

				// ------------------------------------------------------------------------
}
// End Class

/* End of file Cache.php */
/* Location: ./system/libraries/Cache/Cache.php */